1. Field of the Invention
The present invention relates to a plasma arc torch and, more particularly, to a plasma arc torch with improved electrode cooling and/or safety provisions.
2. Description of Related Art
Blowback type plasma torches are generally configured such that an electrode and a nozzle can be brought into contact with each other to ignite an arc, whereafter, the electrode is separated from the nozzle so as to draw the arc therebetween. A fluid, such as air, is concurrently provided under pressure through the nozzle, wherein the air flow interacts with the drawn arc so as to form a plasma. The plasma flowing through the nozzle is then directed at a workpiece to perform a cutting function.
In some instances, the fluid for forming the plasma is also used to cool the electrode and nozzle. That is, the formation of the plasma generally requires a limited amount of, for example, air. As such, the remainder of the fluid can be used for other purposes, such as to cool the electrode and nozzle that are heated by passage of the arc and by the plasma. Cooling of the electrode and nozzle may provide, for example, greater plasma stability and cutting performance, and may also lengthen the service life of the torch components. In some instances, such torches may also be configured to have a relatively compact size, with respect to both the components and the overall assembly. Accordingly, another consideration with these torches is safety, since the torch must incorporate a power feed for providing the arc, and must provide sufficient cooling to prevent catastrophic failure of the torch due to overheating. These considerations must also be implemented in the components of the torch assembly, since proper cooperation of the torch components may also be critical to safety and efficient performance.
Thus, there exists a need for a plasma arc torch, particularly a blowback type of plasma arc torch, having improved electrode and/or nozzle cooling characteristics for providing, for example, greater plasma stability, enhanced and/or consistent cutting performance, and an improved service life. Such a blowback type plasma torch should also facilitate safety, for example, by providing components configured to be formed into a torch assembly in a precise and consistent manner.